Editing Pyruvate kinase (section)

==== Phenylalanine inhibition ====
Phenylalanine is found to function as a competitive inhibitor of pyruvate kinase in the brain. Although the degree of phenylalanine inhibitory activity is similar in both fetal and adult cells, the enzymes in the fetal brain cells are significantly more vulnerable to inhibition than those in adult brain cells. A study of PKM2 in babies with the genetic brain disease [[Phenylketonuria|phenylketonurics]] (PKU), showed elevated levels of phenylalanine and decreased effectiveness of PKM2. This inhibitory mechanism provides insight into the role of pyruvate kinase in brain cell damage.<ref>{{cite journal | vauthors = Miller AL, Hawkins RA, Veech RL | title = Phenylketonuria: phenylalanine inhibits brain pyruvate kinase in vivo | journal = Science | volume = 179 | issue = 4076 | pages = 904–6 | date = March 1973 | pmid = 4734564 | doi = 10.1126/science.179.4076.904 | bibcode = 1973Sci...179..904M | s2cid = 12776382 }}</ref><ref>{{cite journal | vauthors = Weber G | title = Inhibition of human brain pyruvate kinase and hexokinase by phenylalanine and phenylpyruvate: possible relevance to phenylketonuric brain damage | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 63 | issue = 4 | pages = 1365–9 | date = August 1969 | pmid = 5260939 | pmc = 223473 | doi = 10.1073/pnas.63.4.1365 | bibcode = 1969PNAS...63.1365W | doi-access = free }}</ref>